Such an apparatus is known, for example, from DE 44 42 152 A1.
In the treatment apparatus known from DE 44 42 152 A1, the parts to be treated are fed to so-called “virtual chambers” and in these virtual chambers are conveyed through processing treatments. This treatment apparatus comprises a plurality of circular bases disposed with spacing one above the other, which are enclosed by a wall cylinder and between which there is in each case a system of blades disposed at uniform angular intervals. The blade systems rotate jointly relative to the bases, wherein each base has a window and the windows of successive bases in the direction of passage of the workpieces are disposed offset relative to one another counter to the direction of rotation of the blade systems so that the workpieces, which are fed in each case into a “virtual chamber” delimited by two blades, complete in each case a partial circuit along the bases to the window of the relevant base and, there, then fall onto the base situated underneath, where they then complete the next partial circuit. The chambers in this apparatus are described as “virtual” because in the course of conveying the workpiece they continuously exchange their real bottom and top walls.
The treatment apparatus known from DE 44 42 152 A1 is provided for the processing treatment of small workpieces, which are not damaged by the drop through a base window from one level to the next level of the treatment apparatus.
Particularly in the case of heavier workpieces having a surface that should not be damaged, an uncontrolled drop from one level to another level of the treatment apparatus does however present a considerable risk.